| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a radio receiving circuit which is compact and low-cost, and which operates in a broadband. Ž<P>SOLUTION: According to a state that the frequency of interference waves, obtained by extracting a part of a received signal and inputting the extracted signal together with the received signal is higher or lower than the frequency of a received signal wave, the radio receiving circuit oscillates the frequency to be lower or higher than the frequency of the received signal wave as the local oscillation frequency. A mixer to which the received signal and the local oscillation frequency are inputted performs frequency conversion as an intermediate frequency signal wave of a frequency lower that of the frequency of unwanted radio waves. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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